CRF receptor antagonists and methods relating thereto

ABSTRACT

CRF receptor antagonists are disclosed which have utility in the treatment of a variety of disorders, including the treatment of disorders manifesting hypersecretion of CRF in a warm-blooded animal, such as stroke. The CRF receptor antagonists of this invention have the following structure:  
                 
 
     including stereoisomers and pharmaceutically acceptable salts thereof, wherein m, R, R 1 , R 2 , A, and X are as defined herein. Compositions containing a CRF receptor antagonist in combination with a pharmaceutically acceptable carrier are also disclosed, as well as methods for use of the same.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation of U.S. application Ser. No.09/861,472 filed May 18, 2001, which claims the benefit of U.S.Provisional Application No. 60/205,649 filed May 18, 2000.

TECHNICAL FIELD

[0002] This invention relates generally to CRF receptor antagonists, andto methods of treating disorders by administration of such antagoniststo a warm-blooded animal in need thereof.

BACKGROUND OF THE INVENTION

[0003] The first corticotropin-releasing factor (CRF) was isolated fromovine hypothalmi and identified as a 41-amino acid peptide (Vale et al.,Science 213:1394-1397, 1981). Subsequently, sequences of human and ratCRF were isolated and determined to be identical, but different fromovine CRF in 7 of the 41 amino acid residues (Rivier et al., Proc. Natl.Acad. Sci. USA 80:4851, 1983; Shibahara et al., EMBOJ 2:775, 1983).

[0004] CRF has been found to produce profound alterations in endocrine,nervous and immune system function. CRF is believed to be the majorphysiological regulator of the basal and stress-release ofadrenocorticotropic hormone (“ACTH”), β-endorphin, and otherpro-opiomelanocortin (“POMC”)-derived peptides from the anteriorpituitary (Vale et al., Science 213:1394-1397, 1981). Briefly, CRF isbelieved to initiate its biological effects by binding to a plasmamembrane receptor which has been found to be distributed throughout thebrain (DeSouza et al., Science 224:1449-1451, 1984), pituitary (DeSouzaet al., Methods Enzymol. 124:560, 1986; Wynn et al., Biochem. Biophys.Res. Comm. 110:602-608, 1983), adrenals (Udelsman et al., Nature319:147-150, 1986) and spleen (Webster, E. L., and E. B. DeSouza,Endocrinology 122:609-617, 1988). The CRF receptor is coupled to aGTP-binding protein (Perrin et al., Endocrinology 118:1171-1179, 1986)which mediates CRF-stimulated increase in intracellular production ofcAMP (Bilezikjian, L. M., and W. W. Vale, Endocrinology 113:657-662,1983). The receptor for CRF has now been cloned from rat (Perrin et al.,Endo 133(6):3058-3061, 1993), and-human brain (Chen et al., PNAS90(19):8967-8971, 1993; Vita et al., FEBS 335(1):1-5, 1993). Thisreceptor is a 415 amino acid protein comprising seven membrane spanningdomains. A comparison of identity between rat and human sequences showsa high degree of homology (97%) at the amino acid level.

[0005] In addition to its role in stimulating the production of ACTH andPOMC, CRF is also believed to coordinate many of the endocrine,autonomic, and behavioral responses to stress, and may be involved inthe pathophysiology of affective disorders. Moreover, CRF is believed tobe a key intermediary in communication between the immune, centralnervous, endocrine and cardiovascular systems (Crofford et al., J. Clin.Invest. 90:2555-2564, 1992; Sapolsky et al., Science 238:522-524, 1987;Tilders et al., Regul. Peptides 5:77-84, 1982). Overall, CRF appears tobe one of the pivotal central nervous system neurotransmitters and playsa crucial role in integrating the body's overall response to stress.

[0006] Administration of CRF directly to the brain elicits behavioral,physiological, and endocrine responses identical to those observed foran animal exposed to a stressful environment. For example,intracerebroventricular injection of CRF results in behavioralactivation (Sutton et al., Nature 297:331, 1982), persistent activationof the electroencephalogram (Ehlers et al., Brain Res. 278:332, 1983),stimulation of the sympathoadrenomedullary pathway (Brown et al.,Endocrinology 110:928, 1982), an increase of heart rate and bloodpressure (Fisher et al., Endocrinology 110:2222, 1982), an increase inoxygen consumption (Brown et al., Life Sciences 30:207, 1982),alteration of gastrointestinal activity (Williams et al., Am. J.Physiol. 253:G582, 1987), suppression of food consumption (Levine etal., Neuropharmacology 22:337, 1983), modification of sexual behavior(Sirinathsinghji et al., Nature 305:232, 1983), and immune functioncompromise (Irwin et al., Am. J. Physiol. 255:R744, 1988). Furthermore,clinical data suggests that CRF may be hypersecreted in the brain indepression, anxiety-related disorders, and anorexia nervosa. (DeSouza,Ann. Reports in Med. Chem. 25:215-223, 1990). Accordingly, clinical datasuggests that CRF receptor antagonists may represent novelantidepressant and/or anxiolytic drugs that may be useful in thetreatment of the neuropsychiatric disorders manifesting hypersecretionof CRF.

[0007] The first CRF receptor antagonists were peptides (see, e.g.,Rivier et al., U.S. Pat. No. 4,605,642; Rivier et al., Science 224:889,1984). While these peptides established that CRF receptor antagonistscan attenuate the pharmacological responses to CRF, peptide CRF receptorantagonists suffer from the usual drawbacks of peptide therapeuticsincluding lack of stability and limited oral activity. More recently,small molecule CRF receptor antagonists have been reported. For example,substituted 4-thio-5-oxo-3-pyrazoline derivatives (Abreu et al., U.S.Pat. No. 5,063,245) and substituted 2-aminothiazole derivatives(Courtemanche et al., Australian Patent No. AU-A-41399/93) have beenreported as CRF receptor antagonists. These particular derivatives werefound to be effective in inhibiting the binding of CRF to its receptorin the 1-10 μM range and 0.1-10 μM range, respectively.

[0008] Due to the physiological significance of CRF, the development ofbiologically-active small molecules having significant CRF receptorbinding activity and which are capable of antagonizing the CRF receptorremains a desirable goal. Such CRF receptor antagonists would be usefulin the treatment of endocrine, psychiatric and neurologic conditions orillnesses, including stress-related disorders in general.

[0009] While significant strides have been made toward achieving CRFregulation through administration of CRF receptor antagonists, thereremains a need in the art for effective small molecule CRF receptorantagonists. There is also a need for pharmaceutical compositionscontaining such CRF receptor antagonists, as well as methods relating tothe use thereof to treat, for example, stress-related disorders. Thepresent invention fulfills these needs, and provides other relatedadvantages.

SUMMARY OF THE INVENTION

[0010] In brief, this invention is generally directed to CRF receptorantagonists, and more specifically to CRF receptor antagonists havingthe following general structure (I):

[0011] including stereoisomers, prodrugs and pharmaceutically acceptablesalts thereof, wherein m, R, R₁, R₂, A and X are as defined below.

[0012] The CRF receptor antagonists of this invention have utility overa wide range of therapeutic applications, and may be used to treat avariety of disorders or illnesses, including stress-related disorders.Such methods include administering an effective amount of a CRF receptorantagonist of this invention, preferably in the form of a pharmaceuticalcomposition, to an animal in need thereof. Accordingly, in anotherembodiment, pharmaceutical compositions are disclosed containing one ormore CRF receptor antagonists of this invention in combination with apharmaceutically acceptable carrier and/or diluent.

[0013] These and other aspects of the invention will be apparent uponreference to the following detailed description. To this end, variousreferences are set forth herein which describe in more detail certainprocedures, compounds and/or compositions, and are hereby incorporatedby reference in their entirety.

DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention is directed generally to compounds usefulas corticotropin-releasing factor (CRF) receptor antagonists.

[0015] In a first embodiment, the CRF receptor antagonists of thisinvention have the following structure (I):

[0016] including stereoisomers, prodrugs and pharmaceutically acceptablesalts thereof,

[0017] wherein:

[0018] X is nitrogen or CR₃;

[0019] A is O, S or NR₄;

[0020] “- - -” represents an optional double bond;

[0021] R is an optional substituent which, at each occurrence, isindependently alkyl, aryl, heteroaryl, alkylidenyl, arylalkyl orheteroarylalkyl, wherein m is 0, 1, 2 or 3 and represents the number ofR substituents;

[0022] R₁ is alkyl, substituted alkyl, aryl, substituted aryl,heteroaryl or substituted heteroaryl;

[0023] R₂ is hydrogen, halogen, cyano, alkyl, substituted alkyl, alkoxyor thioalkyl;

[0024] R₃ is hydrogen, halogen, alkyl or substituted alkyl; and

[0025] R₄ is hydrogen, alkyl, substituted alkyl, aryl, substituted aryl,heterocycle or substituted heterocycle.

[0026] As used herein, the above terms have the following meaning:

[0027] “Alkyl” means a straight chain or branched, noncyclic or cyclic,unsaturated or saturated aliphatic hydrocarbon containing from 1 to 10carbon atoms, while the term “lower alkyl” has the same meaning as alkylbut contains from 1 to 6 carbon atoms. Representative saturated straightchain alkyls include methyl, ethyl, n-propyl, n-butyl, n-pentyl,n-hexyl, and the like; while saturated branched alkyls includeisopropyl, sec-butyl, isobutyl, tert-butyl, isopentyl, and the like.Representative saturated cyclic alkyls include cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, —CH₂cyclopropyl, —CH₂cyclobutyl,—CH₂cyclopentyl, —CH₂cyclohexyl, and the like; while unsaturated cyclicalkyls include cyclopentenyl and cyclohexenyl, and the like. Cyclicalkyls, also referred to as “homocyclic rings,” include di- andpoly-homocyclic rings such as decalin and adamantly. Unsaturated alkylscontain at least one double or triple bond between adjacent carbon atoms(referred to as an “alkenyl” or “alkynyl”, respectively). Representativestraight chain and branched alkenyls include ethylenyl, propylenyl,1-butenyl, 2-butenyl, isobutylenyl, 1-pentenyl, 2-pentenyl,3-methyl-1-butenyl, 2-methyl-2-butenyl, 2,3-dimethyl-2-butenyl, and thelike; while representative straight chain and branched alkynyls includeacetylenyl, propynyl, 1-butynyl, 2-butynyl, 1-pentynyl, 2-pentynyl,3-methyl-1 butynyl, and the like.

[0028] “Alkylidenyl” represents a divalent alkyl from which two hydrogenatoms are taken from the same carbon atom, such as ═CH₂, ═CHCH₃,═CHCH₂CH₃, C(CH₃)CH₂CH₃, and the like.

[0029] “Aryl” means an aromatic carbocyclic moiety such as phenyl ornaphthyl.

[0030] “Arylalkyl” means an alkyl having at least one alkyl hydrogenatoms replaced with an aryl moiety, such as benzyl (i.e., —CH₂phenyl),—CH₂-(l or 2-naphthyl), —(CH₂)₂phenyl, —(CH₂)₃phenyl, —CH(phenyl)₂, andthe like.

[0031] “Heteroaryl” means an aromatic heterocycle ring of 5- to10-members and having at least one heteroatom selected from nitrogen,oxygen and sulfur, and containing at least 1 carbon atom, including bothmono- and bicyclic ring systems. Representative heteroaryls include (butare not limited to) furyl, benzofuranyl, thiophenyl, benzothiophenyl,pyrrolyl, indolyl, isoindolyl, azaindolyl, pyridyl, quinolinyl,isoquinolinyl, oxazolyl, isooxazolyl, benzoxazolyl, pyrazolyl,imidazolyl, benzimidazolyl, thiazolyl, benzothiazolyl, isothiazolyl,pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, cinnolinyl,phthalazinyl, and quinazolinyl.

[0032] “Heteroarylalkyl” means an alkyl having at least one alkylhydrogen atom replaced with a heteroaryl moiety, such as —CH₂pyridinyl,—CH₂pyrimidinyl, and the like.

[0033] “Heterocycle” (also referred to herein as a “heterocycle ring”)means a 5- to 7-membered monocyclic, or 7- to 14-membered polycyclic,heterocycle ring which is either saturated, unsaturated or aromatic, andwhich contains from 1 to 4 heteroatoms independently selected fromnitrogen, oxygen and sulfur, and wherein the nitrogen and sulfurheteroatoms may be optionally oxidized, and the nitrogen heteroatom maybe optionally quaternized, including bicyclic rings in which any of theabove heterocycles are fused to a benzene ring as well as tricyclic (andhigher) heterocyclic rings. The heterocycle may be attached via anyheteroatom or carbon atom. Heterocycles include heteroaryls as definedabove. Thus, in addition to the aromatic heteroaryls listed above,heterocycles also include (but are not limited to) morpholinyl,pyrrolidinonyl, pyrrolidinyl, piperidinyl, hydantoinyl, valerolactamyl,oxiranyl, oxetanyl, tetrahydrofuranyl, tetrahydropyranyl,tetrahydropyridinyl, tetrahydroprimidinyl, tetrahydrothiophenyl,tetrahydrothiopyranyl, tetrahydropyrimidinyl, tetrahydrothiophenyl,tetrahydrothiopyranyl, and the like.

[0034] “Heterocyclealkyl” means an alkyl having at least one alkylhydrogen atom replaced with a heterocycle, such as —CH₂morpholinyl, andthe like.

[0035] The term “substituted” as used herein means any of the abovegroups (i.e, alkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl,heterocycle and heterocyclealkyl) wherein at least one hydrogen atom isreplaced with a substituent. In the case of a keto substituent(“—C(═O)—”) two hydrogen atoms are replaced. “Substituents” within thecontext of this invention include halogen, hydroxy, cyano, nitro, amino,alkylamino, dialkylamino, alkyl, alkoxy, thioalkyl, haloalkyl,hydroxyalkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl,heteroaryl, substituted heteroaryl, heteroarylalkyl, substitutedheteroarylalkyl, heterocycle, substituted heterocycle, heterocyclealkyl,substituted heterocyclealkyl, —NR_(a)R_(b), —NR_(a)C(═O)R_(b),—NR_(a)C(═O)NR_(a)R_(b), —NR_(a)C(═O)OR_(b)—NR_(a)SO₂R_(b), —R_(a),—C(═O)R_(a) —C(═O)OR_(a), —C(═O)NR_(a)R_(b), —OC(═O)NR_(a)R_(b), —SH,—SR_(a), —SOR_(a), —S(═O)₂R_(a), —OS(═O)₂R_(a), —S(═O)₂OR_(a), whereinR_(a) and R_(b) are the same or different and independently hydrogen,alkyl, haloalkyl, substituted alkyl, aryl, substituted aryl, arylalkyl,substituted arylalkyl, heteroaryl, substituted heteroaryl,heteroarylalkyl, substituted heteroarylalkyl, heterocycle, substitutedheterocycle, heterocyclealkyl or substituted heterocyclealkyl.

[0036] “Halogen” means fluoro, chloro, bromo and iodo.

[0037] “Haloalkyl” means an alkyl having at least one hydrogen atomreplaced with halogen, such as trifluoromethyl and the like. Haloalkylis a specific embodiment of substituted alkyl, wherein alkyl issubstituted with one or more halogen atoms.

[0038] “Alkoxy” means an alkyl moiety attached through an oxygen bridge(i.e., —O-alkyl) such as —O-methyl, —O-ethyl, and the like.

[0039] “Thioalkyl” means an alkyl moiety attached through a sulfurbridge (i.e., —S-alkyl) such as —S-methyl, —S-ethyl, and the like.

[0040] “Alkylamino” and “dialkylamino mean one or two alkyl moietiesattached through a nitrogen bridge (i.e., —NHalkyl or —N(alkyl)(alkyl))such as methylamino, ethylamino, dimethylamino, diethylamino, and thelike.

[0041] “Hydroxyalkyl” means an alkyl substituted with at least onehydroxyl group.

[0042] Depending upon the A and X groups, representative compounds ofthis invention have one of the following structures (II) through (VI):

[0043] As used in the context of this invention,

[0044] represents —CH₂CH₂— or —CH═CH— optionally substituted with 1, 2or 3 R substituents (i.e., m=0, 1, 2 or 3). Accordingly, representativecompounds of this invention include (but are not limited to) compoundshaving the following structures (1a) through (1i), where each occurrenceof R is the same or different and represents a group (other thanhydrogen) as defined previously:

[0045] When present, representative R groups of this invention includealkyl (such as methyl, ethyl, n-propyl, isopropyl and isobutyl), aryl(such as phenyl), heteroaryl (such as pyridyl), and alkylidenyl (such as═CH₂ and ═CHCH₃). In the case of R being an alkylidenyl, the carbon atomto which it is attached must have the appropriate valency. For example,an alkuylidenyl moiety would not be appropriate at the R position shownin structure (1g) above.

[0046] In more specific embodiments of this invention, representative R₁groups of this invention include (but are not limited to)2,4-dichlorophenyl, 2,4-dimethyl-phenyl, 2-chloro-4-methylphenyl,2-methyl-4-chlorophenyl, 2,4,6-trimethylphenyl, 2,4,5-trimethylphenyl,2-chloro-4,5-dimethoxyphenyl, 2-chloro-4-methoxyphenyl,2-methyl-4-methoxyphenyl, 2,4-dimethoxyphenyl,2-trifluoromethyl-4-chlorophenyl, 3-methoxy-4-chlorophenyl,2,5-dimethoxy-4-chlorophenyl, 2-methoxy-4-trifluoromethylphenyl,2-methoxy-4-isopropylphenyl, 2-methoxy-4-trifluoromethylphenyl,2-methoxy-4-isopropylphenyl 2-methoxy-4-methylphenyl,4-methyl-6-dimethylaminopyridin-3-yl,4-dimethylamino-6-methyl-pyridin-3-yl, 6-dimethylamino-pyridin-3-yl and4-dimethylamino-pyridin-3-yl.

[0047] Similarly, representative R₂ groups include hydrogen methyl,ethyl, thiomethyl, trifluoromethyl and methoxy, representative R₃ groupsinclude hydrogen, methyl, ethyl, chloro and fluoro, and representativeR₄ groups include alkyl such as 4-heptyl, hexyl, pentyl and substitutedalkyl such as methoxy or dimethoxy substituted propyl, pentyl andheptyl.

[0048] The compounds of the present invention may generally be utilizedas the free base. Alternatively, the compounds of this invention may beused in the form of acid addition salts. Acid addition salts of the freebase amino compounds of the present invention may be prepared by methodswell known in the art, and may be formed from organic and inorganicacids. Suitable organic acids include maleic, fumaric, benzoic,ascorbic, succinic, methanesulfonic, acetic, oxalic, propionic,tartaric, salicylic, citric, gluconic, lactic, mandelic, cinnamic,aspartic, stearic, palmitic, glycolic, glutamic, and benzenesulfonicacids. Suitable inorganic acids include hydrochloric, hydrobromic,sulfuric, phosphoric, and nitric acids. Thus, the term “pharmaceuticallyacceptable salt” of structure (I) is intended to encompass any and allacceptable salt forms.

[0049] In general, the compounds of structure (I) may be made accordingto the organic synthesis techniques known to those skilled in thisfield, as well as by the representative methods set forth in theExamples. For example, the synthesis of structure (I) may generallyproceed according to the following Reaction Schemes 1 through 3.

[0050] The effectiveness of a compound as a CRF receptor antagonist maybe determined by various assay methods. Suitable CRF antagonists of thisinvention are capable of inhibiting the specific binding of CRF to itsreceptor and antagonizing activities associated with CRF. A compound ofstructure (I) may be assessed for activity as a CRF antagonist by one ormore generally accepted assays for this purpose, including (but notlimited to) the assays disclosed by DeSouza et al. (J. Neuroscience7:88, 1987) and Battaglia et al. (Synapse 1:572, 1987). As mentionedabove, suitable CRF antagonists include compounds which demonstrate CRFreceptor affinity. CRF receptor affinity may be determined by bindingstudies that measure the ability of a compound to inhibit the binding ofa radiolabeled CRF (e.g., [¹²⁵,]tyrosine-CFR) to its receptor (e.g.,receptors prepared from rat cerebral cortex membranes). The radioligandbinding assay described by DeSouza et al. (supra, 1987) provides anassay for determining a compound's affinity for the CRF receptor. Suchactivity is typically calculated from the IC₅₀ as the concentration of acompound necessary to displace 50% of the radiolabeled ligand from thereceptor, and is reported as a “K_(i)” value calculated by the followingequation: $K_{i} = \frac{{IC}_{50}}{1 + {L/K_{D}}}$

[0051] where L=radioligand and K_(D)=affinity of radioligand forreceptor (Cheng and Prusoff, Biochem. Pharmacol. 22:3099, 1973).

[0052] In addition to inhibiting CRF receptor binding, a compound's CRFreceptor antagonist activity may be established by the ability of thecompound to antagonize an activity associated with CRF. For example, CRFis known to stimulate various biochemical processes, including adenylatecyclase activity. Therefore, compounds may be evaluated as CRFantagonists by their ability to antagonize CRF-stimulated adenylatecyclase activity by, for example, measuring cAMP levels. TheCRF-stimulated adenylate cyclase activity assay described by Battagliaet al. (supra, 1987) provides an assay for determining a compound'sability to antagonize CRF activity. Accordingly, CRF receptor antagonistactivity may be determined by assay techniques which generally includean initial binding assay (such as disclosed by DeSouza (supra, 1987))followed by a cAMP screening protocol (such as disclosed by Battaglia(supra, 1987)).

[0053] With reference to CRF receptor binding affinities, CRF receptorantagonists of this invention have a K_(i) of less than 10 μM. In apreferred embodiment of this invention, a CRF receptor antagonist has aK_(i) of less than 1 μM, and more preferably less than 0.25 μM (i.e.,250 nM). As set forth in greater detail below, the K_(i) values ofrepresentative compounds of this invention may be assayed by the methodsset forth in Example 5.

[0054] The CRF receptor antagonists of the present invention demonstrateactivity at the CRF receptor site, and may be used as therapeutic agentsfor the treatment of a wide range of disorders or illnesses includingendocrine, psychiatric, and neurologic disorders or illnesses. Morespecifically, the CRF receptor antagonists of the present invention maybe useful in treating physiological conditions or disorders arising fromthe hypersecretion of CRF. Because CRF is believed to be a pivotalneurotransmitter that activates and coordinates the endocrine,behavioral and automatic responses to stress, the CRF receptorantagonists of the present invention can be used to treatneuropsychiatric disorders. Neuropsychiatric disorders which may betreatable by the CRF receptor antagonists of this invention includeaffective disorders such as depression; anxiety-related disorders suchas generalized anxiety disorder, panic disorder, obsessive-compulsivedisorder, abnormal aggression, cardiovascular abnormalities such asunstable angina and reactive hypertension; and feeding disorders such asanorexia nervosa, bulimia, and irritable bowel syndrome. CRF antagonistsmay also be useful in treating stress-induced immune suppressionassociated with various diseases states, as well as stroke. Other usesof the CRF antagonists of this invention include treatment ofinflammatory conditions (such as rheumatoid arthritis, uveitis, asthma,inflammatory bowel disease and G.I. motility), pain, Cushing's disease,infantile spasms, epilepsy and other seizures in both infants andadults, and various substance abuse and withdrawal (includingalcoholism).

[0055] In another embodiment of the invention, pharmaceuticalcompositions containing one or more CRF receptor antagonists aredisclosed. For the purposes of administration, the compounds of thepresent invention may be formulated as pharmaceutical compositions.Pharmaceutical compositions of the present invention comprise a CRFreceptor antagonist of the present invention (i.e., a compound ofstructure (I)) and a pharmaceutically acceptable carrier and/or diluent.The CRF receptor antagonist is present in the composition in an amountwhich is effective to treat a particular disorder—that is, in an amountsufficient to achieve CRF receptor antagonist activity, and preferablywith acceptable toxicity to the patient. Preferably, the pharmaceuticalcompositions of the present invention may include a CRF receptorantagonist in an amount from 0.1 mg to 250 mg per dosage depending uponthe route of administration, and more preferably from 1 mg to 60 mg.Appropriate concentrations and dosages can be readily determined by oneskilled in the art.

[0056] Pharmaceutically acceptable carrier and/or diluents are familiarto those skilled in the art. For compositions formulated as liquidsolutions, acceptable carriers and/or diluents include saline andsterile water, and may optionally include antioxidants, buffers,bacteriostats and other common additives. The compositions can also beformulated as pills, capsules, granules, or tablets which contain, inaddition to a CRF receptor antagonist, diluents, dispersing and surfaceactive agents, binders, and lubricants. One skilled in this art mayfurther formulate the CRF receptor antagonist in an appropriate manner,and in accordance with accepted practices, such as those disclosed inRemington's Pharmaceutical Sciences, Gennaro, Ed., Mack Publishing Co.,Easton, Pa. 1990.

[0057] In addition, prodrugs are also included within the context ofthis invention. Prodrugs are any covalently bonded carriers that releasea compound of structure (I) in vivo when such prodrug is administered toa patient. Prodrugs are generally prepared by modifying functionalgroups in a way such that the modification is cleaved, either by routinemanipulation or in vivo, yielding the parent compound. Prodrugs include,for example, compounds of this invention wherein hydroxy, amine orsulfhydryl groups are bonded to any group that, when administered to apatient, cleaves to form the hydroxy, amine or sulfhydryl groups. Thus,representative examples of prodrugs include (but are not limited to)acetate, formate and benzoate derivatives of alcohol and aminefunctional groups of the compounds of structure (I). Further, in thecase of an carboxylic acid (—COOH), esters may be employed, such asmethyl esters, ethyl esters, and the like.

[0058] With regard to stereoisomers, the compounds of structure (I) mayhave chiral centers and may occur as racemates, racemic mixtures and asindividual enantiomers or diastereomers. All such isomeric forms areincluded within the present invention, including mixtures thereof.Furthermore, some of the crystalline forms of the compounds of structure(I) may exist as polymorphs, which are included in the presentinvention. In addition, some of the compounds of structure (I) may alsoform solvates with water or other organic solvents. Such solvates aresimilarly included within the scope of this invention.

[0059] In another embodiment, the present invention provides a methodfor treating a variety of disorders or illnesses, including endocrine,psychiatric and neurologic disorders or illnesses. Such methods includeadministering of a compound of the present invention to a warm-bloodedanimal in an amount sufficient to treat the disorder or illness. Suchmethods include systemic administration of a CRF receptor antagonist ofthis invention, preferably in the form of a pharmaceutical composition.As used herein, systemic administration includes oral and parenteralmethods of administration. For oral administration, suitablepharmaceutical compositions of CRF receptor antagonists include powders,granules, pills, tablets, and capsules as well as liquids, syrups,suspensions, and emulsions. These compositions may also includeflavorants, preservatives, suspending, thickening and emulsifyingagents, and other pharmaceutically acceptable additives. For parentaladministration, the compounds of the present invention can be preparedin aqueous injection solutions which may contain, in addition to the CRFreceptor antagonist, buffers, antioxidants, bacteriostats, and otheradditives commonly employed in such solutions.

[0060] In another embodiment, compounds of this invention and theiranalogs may be used as Positron Emission Tomography (PET) ligands,Single Photon Emission Computed Tomography (SPECT) ligands, or otherdiagnostic radiopharmaceutical agents. Incorporation of an appropriateisotope (such as ¹¹C or ¹⁸F for PET or ¹²⁵I, in the case of SPECT) mayprovide an agent useful for the diagnosis or therapeutic management of apatient. In addition, use of a compound of the present invention mayprovide a physiological, functional, or biological assessment of apatient or provide disease or pathology detection and assessment.

[0061] As mentioned above, administration of a compound of the presentinvention can be used to treat a wide variety of disorders or illnesses.In particular, the compounds of the present invention may beadministered to a warm-blooded animal for the treatment of depression,anxiety disorder, panic disorder, obsessive-compulsive disorder,abnormal aggression, unstable angina, reactive hypertension, anorexianervosa, bulimia, irritable bowel syndrome, stress-induced immunesuppression, stroke, inflammation, pain, Cushing's disease, infantilespasms, epilepsy, and substance abuse or withdrawal.

[0062] The following examples are provided for purposes of illustration,not limitation.

EXAMPLES

[0063] Representative CRF receptor antagonists of this invention may beprepared by the methods disclosed in Examples 1-4. Example 5 presents amethod for determining the receptor binding activity (K_(i)), andExample 6 discloses an assay for screening compounds for CRF-stimulatedadenylate cyclase activity.

Example 1 Synthesis of Representative Compounds

[0064]

[0065] Compound 1-2

[0066] Dissolved 15 g of 2,4 dichlorophenylacetonitrile (1-1) in THF (60mL). The solution was cooled to 0° C. and sodium hydride (60%, 4.19grams, 1.3 equiv) and diethylcarbonate (12.72 mL, 1.3 equiv) were addedslowly. The mixture was refluxed overnight. The product was seen by TLC(R_(f) product=0.33, 20% EtOAc:Hexane) and by GC. The solution wascooled and 1N HCl was added until the mixture was slightly acidic. Themixture was extracted 3 times with 70 mL of ethyl acetate. The organiclayer was washed with brine and dried with magnesium sulfate.Evaporation of excess solvent gave 18 g of an oily brown liquid 1-2.

[0067] Compound 1-3

[0068] Added 100 mL of 9:1 ethanol:water solution to compound 1-2.Hydrazine (2.2 mL, 1.0 equiv) was added and the mixture was refluxedovernight. Product by TLC stays on baseline with 50% ethylacetate:hexanesolvent system. The ethanol was evaporated from the solution yielding ayellow solid. The solid was washed with approximately 100 mL of etherand was dried in an oven for 3 days to give 11.62g of 1-3 (59% yield).

[0069] Compound 1-4

[0070] Dissolved 11.27 g of compound 1-3 in anhydrous dioxane (100 mL)and added 7.1 mL (1.2 equiv) of ethylacetoacetate and a few crystals ofpTSA. The cloudy mixture was refluxed at 109° C. overnight. The solutionwas allowed to cool and a white solid settled to the bottom. The solidwas filtered and washed 3× with ethyl ether. The solid was dried to give14.48 g (58% yield) of white solid 1-4.

[0071] Compound 1-5

[0072] Added 10 mL of DMF to 1 g of compound 1-4 and heated untilcompletely dissolved. The solution was cooled and sodium hydride (60% inoil, 0.19 g, 1.5 eq) and ethylbromoacetate (0.44 mL, 1.2 equiv) wereadded. The mixture was stirred under nitrogen for 3 hours. 1N HCl wasadded to the solution until the pH was approximately 7 and the mix wasextracted with ethyl acetate (3×10 mL). The organic layer was washedwith brine and dried with magnesium sulfate to yield 0.75 g of 1-5 as awhite solid with an R_(f) of 0.34 using 100% ethylacetate.

[0073] Compound 1-6

[0074] 750 mg of compound 1-5 and 1 mL phoshorous oxychloride was heatedovernight. Ice water and sodium bicarbonate were added until thereaction mixture was neutral. The mixture was extracted with ethylacetate (3×). The organic layer was washed with brine and dried withmagnesium sulfate. The resulting dark reddish/brown oil was filteredthrough a plug of silica gel. Compound 1-6 (0.56 g) was collected as abrown oil. TLC R_(f) of 1-6 was 0.62 using a 1:1 solution of ethylacetate:hexane.

[0075] Compound 1-7

[0076] Compound 1-6 was dissolved in 4 mL of anhydrous acetonitrile.4-Heptylamine (2 mL) was added and the reaction mixture was refluxed at90° C. for 5 hours. The reaction mixture was concentrated in vacuo,diluted with ethyl acetate and filtered through a silica gel plug.Concentration and drying overnight gave 0.502 g of product 1-7.

[0077] Compound 1-8

[0078] Anhydrous THF (2 mL) and 0.01 g (1.0 equiv) of lithium aluminumhydride were stirred under nitrogen. Compound 1-7 (250 mg) in 3 mL ofTHF was added and the solution was stirred for 1.5 hours then refluxedat 70° C. overnight. The THF was evaporated and the resulting mixturewas diluted with water, neutralized with IN HCl and extracted with ethylacetate (3×10 mL). The organic layer was washed with brine and driedwith magnesium sulfate to give 0.217 g of compound 1-8.

[0079] Compound 1-9

[0080] A mixture of 1-8 (217 mg) and POCl₃ (4 mL) was refluxed overnightand then was stirred for 2 days. Ice water and sodium bicarbonate wereadded until the mixture was neutral followed by extraction with ethylacetate. The organic layer was washed with brine then was dried withmagnesium sulfate. Evaporation of solvent gave 181 mg of compound 1-9.

[0081] Compound 1-10

[0082] Compound 1-9 was dissolved in 5 mL of DMF. Sodium hydride (60% inoil, 0.016 g, 1 equiv) was added and the reaction was stirred undernitrogen for 24 hours. After 24 hours another equivalent of NaH wasadded. The reaction mixture was stirred for an additional 6 hours andthe solvent was evaporated. Water and sodium bicarbonate were addeduntil the mixture was neutral and the mixture was extracted with ethylacetate (3×8 mL). The organic layer was washed with brine, dried overmagnesium sulfate and concentrated in vacuo. Purification using a prepTLC plate and 30% ethyl acetate/hexane as elutant gave compound 1-10(10.5 mg, MS ion=433).

Example 2 Synthesis of Representative Compounds

[0083]

[0084] Compound 2-3

[0085] Sodium hydride (1.5 eq) is added to a solution of cyano compound2-1 in THF. Compound 2-2 (R′ is halogen, cyano, alkoxy; R″ is OH,alkoxy; 1 eq) is added. The mixture is refluxed until no startingmaterial is present. After return to room temperature, the mixture istreated with water. The two layers are separated. The aqueous layer isacidified with 1N HCl, cooled, and filtered to give compound 2-3.

[0086] Compound 2-4

[0087] A suspension of compound 2-3 and hydrazine.HBr (2 eq) in EtOH/H₂O(9/1) is heated at reflux for 0.5 hour. Ethanol is removed in vacuo andthe residue is diluted with water. The aqueous phase is made basic withsolid Na₂CO₃ and the product is extracted with ethyl acetate. Theextract is dried with MgSO₄, filtered and concentrated in vacuo to givecompound 2-4.

[0088] Compound 2-5

[0089] Compound 2-4 and substituted ethylacetoacetate (2 eq) in dioxaneis heated at reflux for 20 hours. The suspension is cooled and ether isadded. The solid is collected by filtration. Compound 2-5 is used as isin the next step.

[0090] Compound 2-6

[0091] Compound 2-5 is heated in acetonitrile with an excess of POCl₃.When the conversion is total, the solvent and excess of reagent areremoved. The reaction mixture is neutralized and the product extractedwith CH₂Cl₂. The organic layers are combined and are washed three timeswith water and brine. The organic phase is dried (MgSO₄) andconcentrated in vacuo. Compound 2-6 is purified by silica gelchromatography.

[0092] Compound 2-7

[0093] Compound 2-6 is condensed with one equivalent of thet-butyldiphenyllsilyl protected diol in the presence of sodium hydridein dry DMF. The mixture is then heated at 50° C. for 6 hours. Uponcooling to room temperature the mixture is poured into saturated NH₄Cland is extracted with ethyl acetate. The organic layers are combined andwashed three times with water and brine. The organic phase is dried(MgSO₄) and concentrated in vacuo. Purification via flash chromatographygives the desired product 2-7.

[0094] Compound 2-8

[0095] The silyl protected alcohol 2-7 is treated with 1M Bu4NF in THF.After 3 hours the mixture is washed with water and extracted with EtOAc.The organic phase is dried (MgSO₄) and concentrated in vacuo.Purification via flash chromatography gives the desired desilylatedproduct 2-8.

[0096] Compound 2-9

[0097] The desilylated product 2-8 is then treated with methanesulfonylchloride and triethylamine in CH₂Cl₂ at 0° C. After three hours themixture is washed with saturated NH₄Cl and brine. The organic phase isdried (MgSO₄) and concentrated in vacuo. Without further purificationthe mesylate is treated with NaH in THF at 0° C. After one hour thereaction mixture is poured into saturated NH₄Cl and is extracted withEtOAc. The organic phase is dried (MgSO₄) and concentrated in vacuo.Purification via flash chromatography gives the desired product 9.

Example 3 Synthesis of Representative Intermediate

[0098]

[0099] Compound 3-1

[0100] To 1.5 eq. of R₁C(NH)OEt and 1 eq of pyrazole in acetonitrile isadded 1 eq of glacial acetic acid. The mixture is stirred at roomtemperature for 3 days. It is then concentrated and the precipitate isfiltered off, washed with ether and dried. To an 1 eq NaOEt solution inethanol is added 0.1 eq of the acetamidino solid and 0.8 eq ofdiethylcarbonate [R3=Et]. The mixture is heated at reflux for 18 hours.After cooling, solvent is removed. The residue is dissolved in water anda 1N HCl solution is added slowly until pH=5-6. The aqueous layer isextracted with EtOAc. The organic layers are combined, washed withbrine, dried with MgSO₄ and the solvent evaporated to give the solid3-1.

[0101] Compound 3-2

[0102] Compound 3-1 is heated in acetonitrile with an excess of POCl₃.When the conversion is total, the solvent and excess of reagent areremoved. The reaction mixture is neutralized and the product extractedwith CH₂Cl₂. The organic layers are combined and are washed three timeswith water and brine. The organic phase is dried (MgSO₄) andconcentrated in vacuo. Compound 3-2 is purified by silica gelchromatography.

Example 4 Synthesis of Representative Intermediate

[0103]

[0104] Compound 4-1

[0105] A solution of bromo compound R₁-Br (0.2 mol) in THF (400 mL) iscooled at −78° C. and is treated with BuLi (2.5 M, 88 mL, 0.22 mol)slowly. The mixture is stirred for 20 minutes at −78° C. and DMF (20.1mL, 0.24 mol) is added dropwise. The mixture is stirred for 10 minutes,the cooling bath removed, and the reaction is allowed to warm to roomtemperature. Water is added and the aqueous mixture is extracted withethyl acetate, washed with brine, dried over MgSO₄ and concentrated invacuo to give 4-1.

[0106] Compound 4-2

[0107] A solution of tosylmethyl isocyanide (15.4 g) in dimethoxyethane(50 mL) is added dropwise into a suspension of KOBu-t (10.16 g, 90 mmol)in dimethoxyethane (50 mL) at −60° C. After 10 minutes, a solution ofaldehyde 4-1 (67 mmol) in dimethoxyethane (75 mL) is added dropwise. Themixture is stirred at −50° C. for 30 minutes and is quenched withmethanol (200 mL). The mixture is refluxed for 1 hour, the solventevaporated and the residue partitioned in ethyl acetate/water. Theorganic layer is washed with water, dried over MgSO₄, and filteredthrough a silica pad, eluting with ethyl acetate. The ethyl acetate isconcentrated in vacuo giving compound 4-2 (62 mmol) as an oil. Thiscompound may be used as the starting material in Examples 1 and 2 (i.e.,compounds 1-1 and 2-1).

Example 5 CRF Receptor Binding Activity

[0108] The compounds of this invention may be evaluated for bindingactivity to the CRF receptor by a standard radioligand binding assay asgenerally described by DeSouza et al. (J. Neurosci. 7:88-100, 1987). Byutilizing various radiolabeled CRF ligands, the assay may be used toevaluate the binding activity of the compounds of the present inventionwith any CRF receptor subtype. Briefly, the binding assay involves thedisplacement of a radiolabeled CRF ligand from the CRF receptor.

[0109] More specifically, the binding assay is performed in 1.5 mlEppendorf tubes using approximately 1×10⁶ cells per tube stablytransfected with human CRF receptors. Each tube receives about 0.1 ml ofassay buffer (e.g., Dulbecco's phosphate buffered saline, 10 mMmagnesium chloride, 20 μM bacitracin) with or without unlabeledsauvagine, urotensin I or CRF (final concentration, 1 μM) to determinenonspecific binding, 0.1 ml of [¹²⁵I] tyrosine—ovine CRF (finalconcentration ˜200 pM or approximately the KD as determined by Scatchardanalysis) and 0.1 ml of a membrane suspension of cells containing theCRF receptor. The mixture is incubated for 2 hours at 22° C. followed bythe separation of the bound and free radioligand by centrifugation.Following two washes of the pellets, the tubes are cut just above thepellet and monitored in a gamma counter for radioactivity atapproximately 80% efficiency. All radioligand binding data may beanalyzed using the non-linear least-square curve-fitting program LIGANDof Munson and Rodbard (Anal. Biochem. 107:220, 1990).

EXAMPLE 6 CRF-Stimulated Adenylate Cyclase Activity

[0110] The compounds of the present invention may also be evaluated byvarious functional testing. For example, the compounds of the presentinvention may be screened for CRF-stimulated adenylate cyclase activity.An assay for the determination of CRF-stimulated adenylate cyclaseactivity may be performed as generally described by Battaglia et al.(Synapse 1:572, 1987), with modifications to adapt the assay to wholecell preparations.

[0111] More specifically, the standard assay mixture may contain thefollowing in a final volume of 0.5 ml: 2 mM L-glutamine, 20 mM HEPES,and 1 mM IMBX in DMEM buffer. In stimulation studies, whole cells withthe transfected CRF receptors are plated in 24-well plates and incubatedfor 1 h at 37° C. with various concentrations of CRF-related andunrelated peptides in order to establish the pharmacological rank-orderprofile of the particular receptor subtype. Following the incubation,the media is aspirated, the wells rinsed once gently with fresh media,and the media aspirated. To determine the amount of intracellular cAMP,300 μl of a solution of 95% ethanol and 20 mM aqueous hydrochloric acidis added to each well and the resulting suspensions are incubated at−20° C. for 16 to 18 hours. The solution is removed into 1.5 mlEppendorf tubes and the wells washed with an additional 200 μl ofethanol/aqueous hydrochloric acid and pooled with the first fraction.The samples are lyophilized and then resuspended with 500 μl sodiumacetate buffer. The measurement of cAMP in the samples is performedusing a single antibody kit from Biomedical Technologies Inc.(Stoughton, Mass.). For the functional assessment of the compounds, asingle concentration of CRF or related peptides causing 80% stimulationof cAMP production is incubated along with various concentrations ofcompeting compounds (10⁻¹² to 10⁻⁶ M).

[0112] It will be appreciated that, although specific embodiments of theinvention have been described herein for purposes of illustration,various modifications may be made without departing from the spirit andscope of the invention. Accordingly, the invention is not limited exceptas by the appended claims.

1. A compound having the following structure:

or a stereoisomer, prodrug or pharmaceutically acceptable salt thereof,wherein: X is nitrogen or CR₃; A is O, S or NR₄; “- - -” represents anoptional double bond; R is an optional substituent which, at eachoccurrence, is independently alkyl, aryl, heteroaryl, alkylidenyl,arylalkyl or heteroarylalkyl, wherein m is 0, 1, 2 or 3 and representsthe number of R substituents; R₁ is alkyl, substituted alkyl, aryl,substituted aryl, heteroaryl or substituted heteroaryl; R₂ is hydrogen,halogen, cyano, alkyl, substituted alkyl, alkoxy or thioalkyl; R₃ ishydrogen, halogen, alkyl or substituted alkyl; and R₄ is hydrogen,alkyl, substituted alkyl, aryl, substituted aryl, heterocycle orsubstituted heterocycle.
 2. The compound of claim 1 wherein A is O. 3.The compound of claim 1 wherein A is S.
 4. The compound of claim 1wherein A is NR₄.
 5. The compound of claim 1 wherein X is nitrogen. 6.The compound of claim 1 wherein X is CR₃.
 7. The compound of claim 1wherein R₁ is substituted aryl.
 8. The compound of claim 1 wherein R₁ issubstituted phenyl.
 9. The compound of claim 1 wherein R₂ is alkyl. 10.The compound of claim 1 wherein m is
 0. 11. A composition comprising acompound of claim 1 in combination with a pharmaceutically acceptablecarrier or diluent.
 12. A method for treating a disorder manifestinghypersecretion of CRF in a warm-blooded animal, comprising administeringto the animal an effective amount of the composition of claim
 11. 13.The method of claim 12 wherein the disorder is stroke.
 14. The method ofclaim 12 wherein the disorder is depression.
 15. The method of claim 12wherein the disorder is anxiety.